JPH07228814A - Curable composition for coating - Google Patents

Abstract

PURPOSE:To obtain a curable coating composition containing an acrylic resin having a crosslinkable functional group, a fluoroolefin resin having a crosslikable functional group reactive therewith and an assistant crosslinking agent and giving a coating film resistant to acid rain, scratch, stain and weather. CONSTITUTION:This curable coating composition giving a coating film resistant to acid rain, scratch, stain and weather is produced by compounding (A) a (meth)acrylic copolymer containing a crosslinkable functional group X, having a weight-average molecular weight of 3,000-100,000 and prepared by the radical polymerization of styrene, n-butyl methacrylate, 2-hydroxyethyl methacrylate and methacrylic acid, etc., with (B) a fluoroolefin copolymer containing a crosslinkable functional group Y reactive with the group X, having a weight- average molecular weight of 3,000-100,000 and prepared by the radical copolymerization of chlorotrifluorethylene, cyclohexyl vinyl ether, hydroxybutyl vinyl ether and glycidyl vinyl ether, etc., and (C) an assistant crosslinking agent such as a melamine crosslinking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating resin composition, and more particularly to a curable coating composition excellent in acid rain resistance, scratch resistance, stain resistance and weather resistance. .

[0002]

2. Description of the Related Art Conventionally, acrylic melamine-based paint has been widely used industrially as a top coat for automobile bodies because it is a one-pack type and has excellent coating workability and finished appearance and high cost performance. However, in recent years, acid rain has become a social problem, and the conventional acrylic melamine type has a drawback that the acid resistance of the cross-linking site of melamine is poor.

[0003]

Therefore, in recent years, compounds such as melamine resin, blocked isocyanate, silanol group, etc. as auxiliary cross-linking agents, which are mainly cured by epoxy group or carboxyl group of acrylic resin as a new curing system, have been developed. The added coating composition is promising or has been partially adopted. However, since these coating compositions have an acrylic resin as a main component, they have a drawback of hydrolysis of an acrylic ester bond by an acid, and there is a limit to improvement of acid resistance and stain removal.

Further, since the main component is an acrylic resin, there is a problem that although the initial acid resistance is good, the acid resistance after weather resistance deterioration is lowered. There is also a problem that stains remain on the coating film against contaminants such as bird droppings, and the stain does not recover even after washing with water.

Although a coating composition in which a hydroxyl group-containing fluororesin is crosslinked with melamine or the like has remarkably better coating performance than an acrylic melamine coating, since it also uses melamine, it is acid-resistant under severe test conditions of 80 ° C. or higher. There is a problem with sex.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the various drawbacks of the prior art described above and to provide a new one having excellent stain resistance and weather resistance in addition to acid rain resistance and scratch resistance. To provide a useful curable coating composition.

That is, the present invention provides a (meth) acrylic copolymer (A) having a crosslinkable functional group X, a fluoroolefin copolymer (B) having a crosslinkable functional group Y which reacts with X, and auxiliary crosslinking. A curable coating composition containing the agent (C).

The present invention will be described in detail below. The (meth) acrylic copolymer (A) in the present invention is preferably a copolymer having a polymerized unit based on a derivative of (meth) acrylic acid having a crosslinkable functional group X as an essential component. 1-80 mol% in the polymer, preferably 5-50
It is one containing mol%.

As a derivative of (meth) acrylic acid having a crosslinkable functional group X, when the crosslinkable functional group X is a hydroxyl group, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth)
Acrylate, hydroxyalkyl (meth) acrylate such as hydroxybutyl (meth) acrylate, ring-opening adduct of hydroxyalkyl (meth) acrylate and ε-caprolactone, ring-opening adduct of (meth) acrylic acid and propylene oxide, and ( Examples thereof include ring-opening adducts of (meth) acrylic acid and ethylene oxide.

When the crosslinkable functional group X is an epoxy group, it contains an aliphatic epoxy group-containing (meth) acrylate such as glycidyl (meth) acrylate and an alicyclic epoxy group-containing such as 3,4-epoxycyclohexylmethyl (meth) acrylate. (Meth) acrylate etc. are mentioned.

When the crosslinkable functional group X is a carboxyl group,
Of monocarboxylic acids such as (meth) acrylic acid, polycarboxylic acids such as itaconic acid, fumaric acid, maleic acid, trimellitic acid, monoesters of these carboxylic acids and their carboxylic acid anhydrides and hydroxyl group-containing compounds Examples include adducts.

When the crosslinkable functional group X is a carboxylic acid anhydride group, succinic anhydride, methylsuccinic anhydride, dodecenylsuccinic anhydride, octadecenylsuccinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, Methyl (tetrahydrophthalic anhydride), hexahydrophthalic anhydride, methyl (hexahydrophthalic anhydride), tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, chlorendic anhydride, itaconic acid Examples thereof include anhydrides, citraconic anhydride, maleic anhydride, and the like.

When the crosslinkable functional group X is a hydrolyzable silyl group, specifically, γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) Acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltripropoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryl Roxypropylmethyldipropoxysilane, γ- (meth) acryloxybutylphenyldimethoxysilane, γ
-(Meth) acryloxybutylphenyldiethoxysilane, γ- (meth) acryloxybutylphenyldipropoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropyldimethylethoxysilane, γ Examples include-(meth) acryloxypropylphenylmethylmethoxysilane and γ- (meth) acryloxypropylphenylmethylethoxysilane.

Examples of the other crosslinkable functional group X include silanol group, amino group, carbonyl group, ester group, thiol group and aldehyde group.

Further, other polymerizable monomers constituting the acrylic copolymer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic. Ester of acrylic acid or methacrylic acid such as butyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and monohydric alcohol having 1 to 22 carbon atoms, styrene, vinyltoluene At least one of various polymerizable monomers such as, (meth) acrylonitrile, α-methylstyrene, and acrylamide can be used.

The (meth) acrylic copolymer (A) is produced by a known method. That is, a derivative of (meth) acrylic acid having a crosslinkable functional group X or another polymerizable monomer is added in the presence of an azo-based or peroxide-based radical polymerization initiator at 60 to 180 ° C., more preferably 80 to 180 ° C. 1
It is obtained by continuing the reaction at a reaction temperature of 60 ° C. for 4 to 12 hours.

As the azo radical polymerization initiator, 2,
2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis (2-methylbutyronitrile) and the like are used as the peroxide radical polymerization initiator. , Benzoyl peroxide,
Examples thereof include lauryl peroxide and di-t-butyl peroxide.

The polymerization method is also not particularly limited, but solution polymerization is advantageous in terms of productivity and performance. As the polymerization medium, organic solvents such as aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and esters such as ethyl acetate and n-butyl acetate are used. . If necessary, n-
Chain transfer agents such as dodecyl mercaptan, thioglycolic acid and α-methylstyrene dimer can also be used.

The weight average molecular weight of the (meth) acrylic copolymer (A) is preferably 3,000 to 100,000. When it is less than 3,000, performances such as solvent resistance, water resistance and weather resistance are significantly deteriorated, which is not preferable.

The fluoroolefin copolymer (B) used in the present invention is a copolymer containing a polymerized unit based on a fluoroolefin and a polymerized unit based on an ethylenically unsaturated monomer having a crosslinkable functional group Y. And a copolymer containing a polymerized unit based on an ethylenically unsaturated monomer not containing a crosslinkable functional group Y together with the polymerized unit is particularly preferable.

Fluoroolefin-based polymerized units / ethylenically unsaturated monomer-containing ethylenically unsaturated monomer having crosslinkable functional group Y in the copolymer / ethylenically unsaturated monomer not containing crosslinkable functional group Y The copolymerization ratio of the polymerized units based on the body is 30 to 70 mol% / 1 to 70 mol% / 0
It is 60 mol%, preferably 40 to 60 mol% / 5 to 50 mol% / 0 to 45 mol%.

As the ethylenically unsaturated monomer, ethylenically unsaturated monomers such as vinyl ethers, allyl ethers, isopropenyl ethers, vinyl esters, allyl esters and olefins are preferably used.
Vinyl ethers are particularly preferable from the viewpoints of solvent solubility, control of coating film hardness, weather resistance, alternate copolymerizability, and polymerization yield.

Specific examples thereof include alkyl vinyl ethers or cycloalkyl vinyl ethers having an alkyl group or a cycloalkyl group having about 2 to 8 carbon atoms such as ethyl vinyl ether and cyclohexyl vinyl ether.

The weight average molecular weight of the fluoroolefin copolymer (B) is 3,000 to 100,000.
Is preferable, and if it is less than 3,000, the weather resistance decreases, which is not preferable.

The fluoroolefin in the fluoroolefin copolymer (B) has a general formula CF ₂ ═CFZ (where Z is hydrogen, chlorine, fluorine, a perfluoroalkyl group having 1 to 3 carbon atoms or a C 1 to 3 carbon atom). A compound represented by a perfluoroalkoxy group) is preferably used. Specific examples include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, perfluoropropyl vinyl ether and the like. The fluoroolefins may be used alone or in combination of two or more.

The crosslinkable functional group Y of the fluoroolefin copolymer (B) is a hydroxyl group, an epoxy group,
Examples thereof include a carboxyl group, a carboxylic acid anhydride group, a hydrolyzable silyl group, a silanol group, an amino group, a carbonyl group, an ester group, a thiol group and an aldehyde group.

Examples of ethylenically unsaturated monomers having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxybutyl vinyl ether and hydroxyethyl vinyl ether, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, and hydroxyethyl allyl ether. Examples thereof include hydroxyalkyl alloyl ether, hydroxyalkyl isopropenyl ether such as hydroxybutyl isopropenyl ether, and allyl alcohol.

Of these, hydroxyalkyl vinyl ethers and hydroxyalkyl isopropenyl ethers are preferable, and hydroxyalkyl vinyl ethers are particularly preferable in terms of copolymerizability with fluoroolefins.

Examples of the ethylenically unsaturated monomer having an epoxy group include aliphatic epoxy group-containing ethylenically unsaturated monomers such as glycidyl vinyl ether, glycidyl allyl ether and glycidyl (meth) acrylate, 3,4
Examples thereof include alicyclic epoxy group-containing ethylenically unsaturated monomers such as epoxycyclohexyl vinyl ether and 3,4-epoxycyclohexylmethyl (meth) acrylate. Further, for the same reason as described above, the vinyl ether type is preferable as the ethylenically unsaturated monomer having an epoxy group.

Examples of the ethylenically unsaturated monomer having a carboxylic acid anhydride group include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, hymic acid anhydride, and 1,3-dicarboxylic acid. Carboxy-2-
Propene acid anhydride, 1,2-dicarboxy-4-hexene acid anhydride, 1,6-dicarboxy-4-hexane acid anhydride, vinyl succinic anhydride, allyl succinic anhydride, 1,2- Besides dicarboxylic-4-allylcyclohexane acid anhydride, vinyl trimellitate acid anhydride? , Vinyl acid anhydride of 1,2,3-propanetricarboxylate, acid anhydride of vinyl 1,2,4-butanetricarboxylate, 3- (2 ', 3'-dicarboxypropyl)
An acid anhydride of a polyvalent carboxylic acid vinyl ester such as an acid anhydride of vinyl butyrate or an acid anhydride of 1,2-ethynediadipic acid vinyl; an acid anhydride of 1,2-dicarboxyethyl vinyl ether; Carboxyallyl vinyl ether acid anhydride, 1,2-dicarboxypropyl vinyl ether acid anhydride, 1,2-dicarboxypropyl allyl ether acid anhydride, 3- (2 ′, 3′-dicarboxypropyl) butyl vinyl ether Acid anhydrides of polycarboxylic carboxylic acid vinyl ethers such as acid anhydrides of 1,2-cicarboxy-4-hydroxycyclohexane vinyl ether, acid anhydrides of 1,2,5,6-tetracarboxy-3-hexane Things, 1, 2, 6, 7
-An acid anhydride of tetracarboxy-3-heptene, 1,2
There are vinyl monomers having two or more acid anhydride groups in the molecule, such as acid anhydrides of bis (dicarboxypropionyloxy) ethylene.

As the ethylenically unsaturated monomer having a carboxyl group, carboxyalkyl vinyl ether,
Examples include carboxyalkyl vinyl ester and carboxyalkyl (meth) acrylate. Further, the fluoroolefin-based copolymer containing a polymerized unit based on the hydroxyl group-containing ethylenically unsaturated monomer may be half-esterified with an acid anhydride or the like to convert the hydroxyl group into a carboxyl group.

The ethylenically unsaturated monomer having a hydrolyzable silyl group is a compound having an olefinic unsaturated bond, an alkylene group and a hydrolyzable alkoxysilyl group or silanol group in the molecule. Specifically, allyltrimethoxysilane, allyltriethoxysilane, 3-butenyltrimethoxysilane, 3-butenyltriethoxysilane, 1-methyl-2-propenyltrimethoxysilane, 1-methyl-2-propenyl. Trimethoxysilane, 1-methyl-2-propenyltriethoxysilane, 4-pentenyltrimethoxysilane, 4-pentenyltriethoxysilane, 1-methyl-3-butenyltrimethoxysilane, 1-methyl-3-butynyltriethoxysilane Methoxysilane, 2-methyl-3-butenyltrimethoxysilane, 2-meth Le-3-butenyltriethoxysilane, 5-hexenyltrimethoxysilane, 5-hexenyltriethoxysilane, 1-methyl-4-pentenyltrimethoxysilane, 6-heptenyltrimethoxysilane, 6-heptenyltriethoxysilane , 1-methyl-
5-hexenyltrimethoxysilane, 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, 3-methyl-6-heptenyltrimethoxysilane,
8-nonenyltrimethoxysilane, 8-nonenyltriethoxysilane, 2-methyl-7-octenyltrimethoxysilane, 9-decenyltrimethoxysilane, 9-decenyltriethoxysilane, 2-methyl-8- Nonenyltrimethoxysilane, 10-undecenyltrimethoxysilane, 10-undecenyltrimethoxysilane, 11-
Dodecenyl trimexisilane, 11-dodecenyltriethoxysilane, γ- (meth) acryloxypropyltrihydroxysilane, γ- (meth) acryloxypropylmethyldihydroxysilane, γ- (meth) acryloxybutylphenyldihydroxy Examples thereof include silane and γ- (meth) acryloxypropylphenylmethylhydroxysilane.

The composition ratio of the (meth) acrylic copolymer (A) and the fluoroolefin copolymer (B) of the present invention in the coating composition is not particularly limited, but the weight ratio (A) is used.
/ (B) = 100/1 to 1/100, preferably (A)
/ (B) = 50/1 to 1/50. When it is out of this range, the functional group of the (meth) acrylic copolymer (A) or the fluoroolefin copolymer (B) is
It is not preferable because it easily remains in the coating film and the chemical resistance and weather resistance are reduced.

As the auxiliary crosslinking agent (C), the crosslinkable functional group X of the (meth) acrylic copolymer (A) and / or the crosslinkable functional group Y of the fluoroolefin copolymer (B) are used.
A compound having reactivity with is used. The amount used is 0.1 to 1 with respect to 100 parts by weight of (A) and (B) in total.
The amount is 00 parts by weight, preferably 1 to 50 parts by weight.

Examples of such a cross-linking agent include a melamine cross-linking agent,
Examples include amino resin-based cross-linking agents such as urea resin cross-linking agents and polybasic acid cross-linking agents, and polyisocyanate cross-linking agents such as blocked polyisocyanates.

Examples of the melamine cross-linking agent include butylated melamine, methylated melamine, and epoxy-modified melamine. Depending on the application, various degrees of modification of 0 to 6 can be used, and the degree of self-condensation can also be selected appropriately. it can. Examples of the urea resin crosslinking agent include methylated urea and butylated urea. Further, as the polybasic acid crosslinking agent, long-chain aliphatic dicarboxylic acids, aromatic polyvalent carboxylic acids, acid anhydrides of these carboxylic acids and the like are useful.

Examples of polyisocyanates include m
(Or p) -xylylene diisocyanate, 2,4
(Or 2,6) -tolylene diisocyanate, m (or p) -phenylene diisocyanate, aromatic diisocyanate compounds such as 4,4′-diphenylmethane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2, Four
Aliphatic (alicyclic) diisocyanate compounds such as (or 2,6) -diisocyanate, 1,3- (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, isophorone diisocyanate, dimer acid diisocyanate, diisocyanate compounds and polyols (ethylene glycol, tris (Such as methylolpropane)
And adducts thereof, polymers of diisocyanate compounds and burette type polyisocyanate compounds.

As the blocking agent for the polyisocyanate compound, a volatile low-molecular active hydrogen compound is used, and methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, butyl cellosolve, methyl carbinol, benzyl alcohol, phenyl cellosolve, full Alcohol-based compounds such as furyl alcohol and cyclohexanol, hydroxy tertiary amine compounds such as dimethylaminoethanol and diethylaminoethanol, amine-based compounds such as diphenylamine, phenylnaphthylamine, aniline and carbazole, formaldoxime and acetaldoxime. , Oxime compounds such as methyl ethyl ketoxime, cyclohexanone oxime, dimethyl malonate, diethyl malonate, acetone Active methylene compounds such as ethyl acetate, lactam compounds such as ε-caprolactam, phenol, cresol, xylenol, p-ethylphenol, o-isopropylphenol, α (or β) -naphthol, p-nitrophenol, p -Phenolic compounds such as chlorophenol, butyl mercaptans, mercaptans such as thiophenol, acid amide compounds such as acetanilide and benzamide, imide compounds such as succinimide and maleic imide, imidazole compounds, urea Examples thereof include system compounds, carbamate compounds, imine compounds, and sulfite compounds.

There are various combinations of the crosslinkable functional groups X and Y of the (meth) acrylic copolymer (A) and the fluoroolefin copolymer (B) of the present invention, which is the field of application of the present invention. As a combination when used as a top coat for automobile bodies, etc. [X /
Y] or [Y / X] is [carboxyl group / hydroxyl group],
[Carboxyl group / hydroxyl group and epoxy group], [carboxylic acid anhydride group / epoxy group], [carboxylic acid anhydride group / hydroxyl group and epoxy group], [carboxyl group and hydroxyl group / epoxy group and hydroxyl group], [epoxy group and A combination of [hydroxyl group / hydrolyzable silyl group and hydroxyl group], [hydroxyl group / hydrolyzable silyl group and hydroxyl group] and the like is preferable.

Of course, the combination of the crosslinkable functional groups is not limited to the above-mentioned combination, and the above-mentioned combination may be used as a main crosslinking component, and if necessary, a third crosslinkable functional group may be additionally used in combination. You can also A large number of combinations can be selected according to the following combinations of mutually reactive crosslinkable functional groups.

A carboxyl group, a carboxylic acid anhydride group, an epoxy group and a hydrolyzable silyl group react with the hydroxyl group, and an epoxy group and a hydrolyzable silyl group other than the above hydroxyl group react with the carboxyl group. React, the carboxylic acid anhydride group, in addition to the hydroxyl group, an epoxy group and a hydrolyzable silyl group reacts, for the epoxy group, the hydroxyl group, the carboxyl group, the carboxylic acid anhydride group In addition, the hydrolyzable silyl group reacts, and the hydrolyzable silyl group reacts with the above-mentioned hydroxyl group, carboxyl group, carboxylic acid anhydride group, and epoxy group.

In addition to the components (A), (B) and (C), the composition of the present invention may optionally contain a conventional acrylic resin (having a crosslinkable functional group X) generally used in coating compositions. No), polyester resin, amino resin, epoxy resin, polyurethane resin, etc. can also be mixed. In particular, the composition of the present invention can further increase the crosslink density by mixing a silicone resin having a siloxane bond.

Further, if necessary, a curing catalyst, a rheology modifier (for example, organic bentonite, crosslinked polymer particles, microgel, wax, etc.), a surface modifier, an ultraviolet absorber, a coloring pigment, a metallic pigment, an extender pigment, etc. are blended. be able to.

Examples of the curing catalyst include acids, bases, blocked acids, blocked bases, organic amines, organometallic compounds, and metal chelate compounds.

The coating composition of the present invention is preferably used by dissolving or dispersing the above components in an organic solvent or water, and can be used as a solid color coating, a metallic coating and a clear coating.

[0046]

【Example】

“Synthesis Example of (Meth) acrylic Copolymer” A monomer mixture in which a radical polymerization initiator 2,2-azobis (2-methylbutyronitrile) is appropriately added so as to have a weight average molecular weight shown in Table 1, The same amount of this mixture as n-butanol / Solvesso # 100 (Esso aromatic hydrocarbon) = 20
The mixture was added dropwise to a / 80 (weight ratio) solution at 120 ° C. over 4 hours and aged at the same temperature for 3 hours. The resin characteristic values of the obtained copolymer are shown in Table 1.

[Synthesis Example of Fluoroolefin Copolymer] Polymerization of the monomer mixture shown in Table 2 by appropriately adding a radical polymerization initiator t-butylperoxypivalate so that the weight average molecular weight shown in Table 2 is obtained. I went. The resin characteristic values of the obtained copolymer are shown in Table 2.

"Preparation example of paint for base coat" Stirrer,
A flask equipped with a thermometer and a condenser was charged with 10 parts of n-butanol and 90 parts of toluene, and heated to 100 ° C. 40 parts of methyl methacrylate, 30 parts of ethyl acrylate, 15 parts of n-butyl acrylate,
A raw material consisting of 12 parts of 2-hydroxyethyl methacrylate, 3 parts of methacrylic acid and 1 part of azobisisobutyronitrile was mixed and continuously added dropwise for 4 hours. 3 at the same temperature
By holding for a while, the conversion rate to the resin was increased to obtain an acrylic resin having a solid content of 50% by weight. The weight average molecular weight of this acrylic resin was 40,000.

100 parts of this acrylic resin, U-ban 20
SE-60 (Butylated melamine resin manufactured by Mitsui Toatsu Chemicals,
Solid content 60% by weight) 25 parts, Alpaste # 1700N
14 parts of L (aluminum paste manufactured by Toyo Aluminum Co., Ltd., solid content: 65% by weight) were mixed to obtain a base coat coating composition.

Next, this base coat coating composition was diluted with a mixed solvent of ethyl acetate / toluene / Solvesso # 150 (Aromatic hydrocarbon manufactured by Esso Co.) = 40/30/30 (weight ratio) and Ford cup # 4 was added. And diluted for 13 seconds to obtain a silver metallic base coat paint.

[Examples 1 to 16] Weights shown in Table 3 from the (meth) acrylic copolymers A-1 to A-7 and the fluoroolefin copolymers B-1 to B-8 shown in the synthesis examples. A ratio coating composition was made. Each paint is diluted with a solvent,
Wet-on-wet spray coating on a steel sheet coated with the silver metallic base coat shown in the synthesis example, heat-curing at 140 ° C. for 30 minutes, and dry coating to 40
A clear coating of ~ 45 μm was obtained. The following coating film performance test was conducted for each example, and the results are shown in Table 3 together.

Acid resistance: 0.3 wt of a 10% by weight sulfuric acid aqueous solution
Was spotted on the coated surface, heated at 70 ° C. for 1 hour and washed with water, and the edge depth of the spot portion was measured with a three-dimensional surface roughness meter.

Scratch resistance: A felt impregnated with a cleanser was reciprocated 50 times under a load of 500 g, and the gloss retention was calculated from the initial gloss and the scratch gloss.

Stain removal property: Carbon black is dispersed in water at a concentration of 0.1% by weight, sprayed on a coated plate, and the temperature is 60 ° C.
The operation of baking for 20 minutes is repeated twice, and the operation of washing with water is defined as one cycle, and the stain removal property after 5 cycles is visually evaluated (○: dirt is removed well, Δ: some stains remain, ×: stain is considerably Remain).

Weather resistance: The gloss retention of the coating film after 3000 hours of exposure with a sunshine weather meter was indicated.

"Comparative Examples 1 to 9" Paints were prepared with the formulations shown in Table 4, and test plates were prepared in the same manner as in the examples. The results are shown in Table 4.
Shown in. Also, Comparative Example 5 uses Nacure N as a curing catalyst.
One part of -5225 (amine block of dodecylbenzenesulfonic acid, manufactured by King) was used.

MF is Nikalac MW30 (Melamine resin manufactured by Sanwa Chemical Co., Ltd.), and BI is Coronate # 251.
3 (blocked isocyanate manufactured by Nippon Polyurethane Industry Co., Ltd.).

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

INDUSTRIAL APPLICABILITY The composition of the present invention provides a coating film excellent in acid rain resistance, scratch resistance, stain resistance, weather resistance and the like, and is extremely useful particularly as a top coat for automobile bodies.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyuki Miyazaki, Nobuyuki Miyazaki 3-474 Tsukoshi, Tsukoshi, Kawasaki-ku, Kawasaki-ku, Kanagawa Pref., Asahi Glass Co., Ltd. 3 474 Address 2 Asahi Glass Co., Ltd. Tamagawa Branch Room (72) Inventor Atsuji Kido 4-60 Sunadabashi, Higashi-ku, Aichi Prefecture Nagoya City Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Kazuhiko Hotta East, Nagoya City, Aichi Prefecture 4-60 Sunadabashi, Ku, Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Takeshi Kato 4-1-1, Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Akio Iwamoto Product development, Mitsubishi Rayon Co., Ltd., 4-chome, Sunadabashi, 4-chome, Higashi-ku, Nagoya, Aichi Research house

Claims (9)

[Claims] 1. A (meth) acrylic copolymer (A) having a crosslinkable functional group X, a fluoroolefin copolymer (B) having a crosslinkable functional group Y reactive with X, and an auxiliary crosslinker (C). And a curable coating composition containing 2. The composition according to claim 1, wherein the functional group X is at least one selected from a hydroxyl group, an epoxy group, a carboxyl group, a carboxylic acid anhydride group and a hydrolyzable silyl group. 3. The composition according to claim 1, wherein the functional group Y is at least one selected from a hydroxyl group, an epoxy group, a carboxyl group, a carboxylic acid anhydride group and a hydrolyzable silyl group. 4. The composition according to claim 1, wherein the auxiliary crosslinking agent (C) is an amino resin or a polyisocyanate. 5. A functional group [X / Y] or a combination of [Y / X] is [carboxyl group / hydroxyl group], [carboxyl group / hydroxyl group and epoxy group], [carboxylic anhydride group / epoxy group], [Carboxylic anhydride group / hydroxyl group and epoxy group], [carboxyl group and hydroxyl group / epoxy group and hydroxyl group], [epoxy group and hydroxyl group / hydrolyzable silyl group and hydroxyl group] or [hydroxyl group / hydrolyzable silyl group and hydroxyl group] ] The composition of claim 1 which is 6. The composition ratio of the (meth) acrylic copolymer (A) and the fluoroolefin copolymer (B) is (A) / (B) = 100/1 to 1/100 by weight. The composition of claim 1. 7. The amount of auxiliary cross-linking agent (C) used is (A),
(B) The composition according to claim 1, which is 0.1 to 100 parts by weight based on 100 parts by weight in total. 8. A (meth) acrylic copolymer (A) is a copolymer containing polymerized units based on a derivative of (meth) acrylic acid having a crosslinkable functional group X, and has a weight average molecular weight of 3,000. The composition of claim 1 which is between 100 and 100,000. 9. A fluoroolefin copolymer (B) comprises:
A copolymer containing a polymerized unit based on a fluoroolefin and a polymerized unit based on an ethylenically unsaturated monomer having a crosslinkable functional group Y and having a weight average molecular weight of 3,000 to 1
The composition of claim 1 which is 0,000.